Apparatus for feeding particulate material

ABSTRACT

Apparatus including a substantially closed chamber having an inlet connected to a supply of granular material and an outlet for dispensing the material from the chamber, a valve for opening and closing the outlet, and a device for drawing air from the chamber when the valve is closed so a stream of air is drawn through the inlet to feed material to the chamber from the supply.

United States Patent 1191 Davies 14 1 June 5, 1973 [54] APPARATUS FOR FEEDING PARTICULATE MATERIAL [75] Inventor: Leonard J. L. Davies, Kettering,

England v [73] Assignee: USM Corporation, Flemington, NJ.

[22] Filed: July 8, 1971 211 App]. No.: 160,588

[30] Foreign Application Priority Data July 23, 1970 Great Britain ..35,642/70 [52] US. Cl ..222/l93, 302/59 [51] Int. Cl ..B65g 53/50 [58] Field of Search ..302/2l, 22, 25, 58,

[56] References Cited UNITED STATES PATENTS 3,424,501 l/l969 Young ..302/59 X 1,305,726 6 1919 Leonard et a]. ..302 2s 1,125,032 1/1915 Goodell ....3o2 59 1,781,352 11/1930 Tolman et a1, ....302/59 3,219,394 11/1965 Moss et al.'...... ....302/59 1,772,881 8/1930 Tolman ....302/59 FOREIGN PATENTS OR APPLICATIONS 313,232 12 1917 Germany/. ..302/59 Primary ExaminerRobert S. Ward, Jr. Att0rney-Richard B. Megley and Vincent A. White [57] ABSTRACT Apparatus including a substantially closed chamber having an inlet connected to a supply of granular material and an outlet for dispensing the material from the chamber, a valve for opening and closing the outlet, and a device for drawing air from the chamber when the valve is closed so a stream of air is drawn through the inlet to feed material to the chamber from the supply.

3 Claims, 3 Drawing Figures 7 PATENTEUJUH 5191a 3.737.074

- SHEET 2 or 2 5 f f f APPARATUS FOR FEEDING PARTICULATE MATERIAL BACKGROUND OF THE INVENTION This invention relates generally to improvements in equipment for the handling of particulate material, such as granular plastics material, by feeding the material from a bulk supply to a supply hopper from which the'material is dispensed to an injection or extrusion molding machine. v

In general, plastics injection molding or extrusion machines include a barrel in which granular material is of said period, the control device causes the valve to be moved toward its open position to dispense material from the supply hopper to the feed hopper.

Until the level of material in the feed hopper drops sufficiently, particulate material remains in the vicinity of the outlet and prevents seating of the valve so that pressure in the chamber is not reducedeven on operation of the switch. To this end, particulateplastics material in the vicinity of the outlet becomes lodged between the body portion of the valve and the seating surface of the hopper and prevents complete closing of the valve. At this time, operation of the air-entrainment device draws air, preferentially into the chamber through the partially closed outlet, and fails to reduce pressure within the chamber sufficiently to cause particulate plastics material to be drawn from the store through the conduit and into the chamber.

hopper, such maintenance in general requiring some kind of equipment to avoid constant visual inspection and/or manual handling of bags of the particulate plastics material. Presently available equipment for use in the maintenance of a supply of particulate material in the feed hoppers of injection molding machines is either insufficiently automatic in its operation or is insufficiently robust to withstand continuous operation under factory conditions.

Accordingly, it is one of the various objects of this invention to provide improved equipment for use in such handling of particulate plastics material which does not require more than a small amount of manual observation and yet which is robust and comparatively inexpensive in its construction. To this end and by way of example, the invention provides an ancillary supply hopper for the delivery of particulate material to the feed hopper of an injection molding machine. The supply hopper in its use istypically positioned over such a feed hopper and is adapted to supply a quantity of particulate plastics material from a bulk store of the material.

The supply hopper comprises a chamber, an inlet extending into the chamber connected by a conduit to a bin or other supply of the particulate plastics material. Extending from the chamber is an outlet having an outflanged portion providing a conical seating surface bounding the outlet. A conical valve is movable between a closed position in which a body portion of the valve seats against the conical seating surface and an open position separated therefrom. Also provided is a means to withdraw air from within the chamber to cause a reduced pressure in the chamber. The means comprises an air-entrainment device whereby a jet of air under pressure is blown through a venturi funnel extending from within the chamber to outside the chamber to draw air from the chamber. On creation ofa sufficient reduction in pressure within the chamber, particulate plastics material is drawn from the store on a stream of air along the conduit and through'the inlet into the chamber.

A control device may. be provided, such as a manually operated switch, to cause the valve to be moved toward its closed position and to operate the airentrainment device for a timed period. On completion When no particulate material remains in the vicinity of the outlet, such as when the feed hopper is partially empty, the valve is able to close completely and operation of the air-entrainment device is able to create a sufficiently low pressure in the chamber to draw particulate plastics material from the store into the chamber of the supply hopper. On completion of said period of time, the valve on opening allows the plastics material to fall from the outlet into the feed hopper.

Thus, one feature of the invention provides equipment for the handling of particulate material in which a control signal adapted to initiate supply of particulate material through the inlet into the hopper chamber will be effective only when no particulate material remains in the vicinity of the outlet.

The above and others of the various objects and several features of this invention will become clear from the following description, to be read with reference to the accompanying drawings of the illustrative supply hopper. It will be appreciated that this supply hopper has been selected to illustrate the invention by way of example only and not by way of limitation thereof. It should also be understood that the term air where used herein should be taken to include any gaseous medium and that particulate material may include powders as well as granular material.

In the drawings:

FIG. 1 is a side view partly in section of a supply hopper embodying the invention; and

FIGS. 2 and 3 are enlarged side views, also partly in section, of parts of the hopper.

The illustrative supply hopper is adapted to be secured over a feed hopper (not shown) of an injection molding machine to deliver granular material to the feed hopper. The supply hopper has a generally cylindrical body portion 2 having a detachable lid 4 and an inwardly tapering conical portion 6. The portion 6 extends to an outlet 8 and has a conical outflanged portion 10 provided with a seating surface 11 disposed around the outlet. The body portion 2, the lid 4 and the conical portion 6 together define a chamber 12 to which granular material is to be delivered and from which material is dispensed to the feed hopper. An airentrainment device 20 (FIG. 2) is secured to the lid 4 and includes a venturi funnel 22, an exhaust pipe 24, and a nozzle 28 through which a jet of air under pressure may be blown through the venturi funnel 22 as supplied from a control device through an air pressure line 30. Mounted on the lid and enclosing the airentrainment device is a cage 32 over which a replaceable filter bag 34 issecured.

An air-operated piston/cylinder device 40 is mounted in the conical portion 6- generally coaxial withtheout let 8. Secured to the lower end portion of a piston rod 44 of the device 40 is a conical valve 50. When air 12 cannot be reducedsufficiently to drawmaterial through the inlet 56. Therefore, even when the control switch is operated manually by an operator of the injectionimachine or cyclically by some other means, theoperation of the supply hopper will be self-regulating and will not require constant operator inspection, for

example,,through observation panels as in, prior demoves the valve toward a closed position as shown in 1 i FIG. 1. In the closed position, the valve seats against the frusto-conical seating surface 11 of theoutflanged I portion 10 to close the outlet 8. The hopper; is provided with an inlet 56 which extends generallytangentially into the chamber 12 through an aperture in the body portion 2. Secured to the inlet on the outside of the The control device (not shown) of the illustrative apparatus, adapted to initiate supply of particulate material through the inlet 56 into the chamberl2, maycom prise a timing device and appropriate control valving.

Air under pressure is normally applied to thefline 42,

vices. Furthermore, there is no need for automatic sensing mechanisms to indicate low levels of material in feed hoppers as in equipment heretofore available.

It should be understood that various equivalent devices may be substituted'for those described without impairing the effectiveness of the apparatus. While one convenient form of control device has been referred to itshouldbe obvious that other forms of electrical, fluid and mechanical controls and operating devices could b tl d..F th th ntrols ldb chamber, and extendingto a bulk supply (not shown) u lze m e We e co e oper of granular plastics material, is a flexible conduit 58.

ated periodicallyby an operator or cyclically, as determined by operationof a machine being fed without departing from the scope of the. invention defined by the claims. a j

Having thus describedmy invention what Iclaim as new and desire to secure by Letters Patent; of the United States is: i

1. Apparatus for feeding particulate material includ ing ,a chamber having an outlet and an inlet connected On operation of the switch when no granular material remains in the feed hopper in the vicinity of the outlet 8, the valve 50 seats on the surface 1 land the chamber 12 (with the exception of the outlet for the air-f entrainment device 20 and the inlet 56,) isrelatively granular material from the 'bulk supply. The pressure of the jet of air, and the lowpressure created in the chamber may be suitably tailoredto thepositioningof the bulk supply, the diameter of the conduit 58 and to the size and weight of the granules. When the feedhopper to a supply of said material, a valve for opening and closing said outlet, meansfor moving the valve away from the outlet to dispense material from the chamber in response to a demand signal and, for moving the valve toward the outlet alternately to block dispensing of material in the chamber or to seal said outlet when the chamber is empty of material, means for drawing airfromthe chamber whereby when the valve seals the outlet astream of air is drawn through the inlet to coni vey material from the supply into the chamber and when the valveis blocked fromsealing by material in inglmeans includes an air-entrainment device the v chambenwith aventuri funnel through which a jet of j i 1 pressurized air is blown to draw air from the chamber the 1 harr V p snvey;maten 1rmm the supply. 2.:Apparatus according toclaim l in which the drawthrough, an exhaust tube and the valve moving means includesa;piston/cylinderdevice which moves the "valve away from the outlet when pressurized air is supis full, so that nolfurther material need be fedto the supply hopper, granular material remains in thevicinity of the outlet 8 and thevalve 50 is preventedtrom sieatfv ing on the surface 1 1. Thus, when the control switch is operated and the device20 is activated, air is drawn through the outlet 8 and thepressure in the chamber device. i

plied thereto, pressurizedair being supplied alternately to the air entrainment device and the piston/cylinder 3. Apparatus according "to claim 2 and including a i timingdevice forlimiting the duration of supply of air; ,1

entdevice. a. a

berinsufficientau is drawn through the inlet 

1. Apparatus for feeding particulate material including a chamber having an outlet and an inlet connected to a supplY of said material, a valve for opening and closing said outlet, means for moving the valve away from the outlet to dispense material from the chamber in response to a demand signal and for moving the valve toward the outlet alternately to block dispensing of material in the chamber or to seal said outlet when the chamber is empty of material, means for drawing air from the chamber whereby when the valve seals the outlet a stream of air is drawn through the inlet to convey material from the supply into the chamber and when the valve is blocked from sealing by material in the chamber insufficient air is drawn through the inlet to convey material from the supply.
 2. Apparatus according to claim 1 in which the drawing means includes an air-entrainment device in the chamber with a venturi funnel through which a jet of pressurized air is blown to draw air from the chamber through an exhaust tube and the valve moving means includes a piston/cylinder device which moves the valve away from the outlet when pressurized air is supplied thereto, pressurized air being supplied alternately to the air entrainment device and the piston/cylinder device.
 3. Apparatus according to claim 2 and including a timing device for limiting the duration of supply of air to the air entrainment device. 